The 38 Super was introduced in 1929 to replaced the 38 ACP or 38 AUTO.The 38 Super is the same case size as the 38 ACP cartridge case but with a higher energy level, withnewer and different gun powders. The 38 Super Auto, is also called the 38 Super, and also the 38 Super +P.The 38 Super & 38ACP cartridge is 9x23mm SR (Semi-Rimmed) it is not the same as the 9x23mm Winchester, which is rimless, and a small diameter rim.